Steering sensor assembly

ABSTRACT

Provided is a power steering sensor assembly which is capable of maintaining a stable coupling between a sensing device and a housing without using a separate auxiliary member, and is mounted in an electric power steering system. The power steering sensor assembly includes a sensing device including a plurality of coupling projections formed on an outer circumferential surface thereof; and a first housing having the sensing device housed therein and including a plurality of coupling grooves formed on an inner circumferential surface thereof, the coupling grooves each having an upper end which is opened. When the sensing device is housed in the first housing, the coupling projections of the sensing device are inserted into the coupling grooves of the first housing, respectively, such that the sensing device is coupled to the first housing without being moved in a radial direction and an axial direction.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.13/139,657, filed Jun. 14, 2011, which is the U.S. national stageapplication of international Patent Application No. PCT/KR2009/003580,filed Jul. 1, 2009, which claims priority to Korean Application No.20-2008-0016691, filed Dec. 16, 2008, the disclosures of each of whichare incorporated herein by reference in their entirety.

TECHNICAL FIELD

The present invention relates to a power steering sensor assembly, andmore particularly, to a power steering sensor assembly capable ofrealizing a secure coupling between a sensing device and a housing.

BACKGROUND ART

An electric power steering system refers to a device for changing thedirection of wheels through a steering wheel, in order to change thedirection of a moving car. A recent electric power steering systemincludes a steering angle sensing device and a torque sensing device toprovide driving stability and users' convenience.

The steering angle sensing device refers to a device for sensing asteering degree to control a moving car, and the torque sensing devicerefers to a device for sensing torque applied to a torsion bar toprovide an auxiliary control power such that a steering wheel may besmoothly controlled.

The steering angle sensing device and the torque sensing device may beseparately provided and mounted in the electric power steering system.Alternatively, the steering angle sensing device and the torque sensingdevice may be provided as a single device and mounted in the electricpower steering system.

The steering angle sensing device and the torque sensing device areassembled together with other components such as a housing and thenmounted in the electric power steering system. Hereinafter, the steeringangle sensing device and the torque sensing device are referred to as asensing device, and the steering angle sensing device and an assembly ofother components, the torque sensing device and an assembly of othercomponents, and the steering angle sensing device, the torque sensingdevice, and an assembly of other components, respectively, are referredto as “power steering sensor assembly”, for convenience of description.

Since the sensing device is sensitive to the external environment, thesensing device is mounted in a sealed housing. That is, the powersteering sensor assembly includes the above-described sensing device andfast and second housings for housing the sensing device.

The sensing device positioned in the housing should be fixed inside thehousing. For this structure, an auxiliary member such as an O-ring ismounted on the outer circumferential surface of the sensing device, andthe sensing device is then positioned in the housing.

In such a state, the outer circumferential surface of the O-ring isclosely attached to the inner circumferential surface of the housing.Accordingly, the sensing device is fixed and mounted in the housing.

However, the above-described structure including the sensing devicemounted in the housing has a problem in that an additional member suchas the O-ring should be prepared and coupled to the sensing device.

Furthermore, in an electric power steering system mounted in a vehicleto which an outer force (impact) is repetitively applied, an O-ring maybe distorted from the original position or may come off from the sensingdevice.

DISCLOSURE Technical Problem

Accordingly, the present invention has been made in an effort to solvethe problems occurring in the related art, and an object of the presentinvention is to provide a power steering sensor assembly which iscapable of maintaining a stable coupling between a sensing device and ahousing without using a separate auxiliary member.

Technical Solution

According to one aspect of the present invention, there is provided apower steering sensor assembly mounted in an electric power steeringsystem, including: a sensing device including input and output shaftsconnected to each other and a plurality of coupling projections formedon an outer circumferential surface thereof; and a first housing havingthe sensing device housed therein and including a plurality of couplinggrooves formed on an inner circumferential surface thereof, the couplinggrooves each having an upper end which is opened. When the sensingdevice is housed in the first housing, the coupling projections of thesensing device are inserted into the coupling grooves of the firsthousing, respectively, such that the sensing device is coupled to thefirst housing without being moved in a radial direction and an axialdirection.

The power steering sensor assembly may further include a second housingcoupled to the first housing to separate the sensing device fromoutside.

Each of the coupling projections of the sensing device may include twobar-shaped members separated from each other in a radial direction in astate in which the coupling projections are fixed to the outercircumferential surface of the sensing device, and each of thebar-shaped members may be formed of an elastic material.

The sensing device may include a plurality of contact projections formedon the outer circumferential surface thereof, extended in the radiusdirection, and contacted with an inner circumferential surface of thefirst housing, and each of the contact projections may be disposedbetween two coupling projections.

Advantageous Effects

According to the embodiment of the present invention, the power steeringsensor assembly has such a structure that couples the sensing device tothe housing without using a separate coupling member such as an O-ring.Therefore, the sensing device may be reliably and stably coupled to thehousing, without being moved in the radial direction and the axialdirection.

DESCRIPTION OF DRAWINGS

The above objects, and other features and advantages of the presentinvention will become more apparent after a reading of the followingdetailed description taken in conjunction with the drawings, in which:

FIGS. 1 and 2 are perspective views of a power steering sensor assemblyaccording to an embodiment of the present invention;

FIG. 3 is a plan view of the power steering sensor assembly in a statein which a second housing is removed from the structure illustrated inFIGS. 1 and 2;

FIG. 4 is a perspective view of a sensing device illustrated in FIGS. 1to 3; and

FIG. 5 is an exploded perspective view of the sensing device illustratedin FIG. 4.

BEST MODE

Reference will now be made in greater detail to a preferred embodimentof the invention, an example of which is illustrated in the accompanyingdrawings. Wherever possible, the same reference numerals will be usedthroughout the drawings and the description to refer to the same or likeparts.

In the following descriptions, “sensing device” indicates any one of asteering angle sensing device, a torque sensing device, and acombination of the steering angle sensing device and the torque sensingdevice which are components of an electric power steering system.

FIGS. 1 and 2 are perspective views of a power steering sensor assemblyaccording to an embodiment of the present invention. FIG. 3 is a planview of the power steering sensor assembly in a state in which a secondhousing is removed from the structure illustrated in FIGS. 1 and 2. FIG.4 is a perspective view of a sensing device illustrated in FIGS. 1 to 3.

The power steering sensor assembly 100 according to the embodiment ofthe present invention includes a first housing 110, a sensing device130, and a second housing 120. The first housing 110 has a predeterminedspace formed therein. The sensing device 130 is fixed and positioned inthe first housing 110. The second housing 120 is coupled to the firsthousing 110.

Meanwhile, an input shaft 10 connected to a steering wheel (notillustrated) and an output shaft 20 connected to the input shaft 10through a torsion bar (not illustrated) and connected to wheels (notillustrated) are positioned in a through-hole formed in the center ofthe sensing device 130. Therefore, the sensing device 100 senses asteering angle and/or torque transferred by the input shaft.

Here, the input shaft 10 is extended to the outside through an opening121 formed in the center of the second housing 120 and connected to anexternal member. The output shaft 20 is extended to the outside throughan opening (not illustrated) thrilled in the center of the first housing110 and connected to another external member.

On the upper portion of the inner circumferential surface of the firsthousing 110 in which the sensing device 130 is housed, a plurality ofcoupling grooves 111, 112, and 113 are formed. The coupling grooves 111,112, and 113 are arranged at a predetermined distance from each other,and respectively have an upper end which is opened. Each of the couplinggrooves 111, 112, and 113 has a predetermined width and depth.

On the outer circumferential surface of the sensing device 130, aplurality of coupling projections 131, 132, and 133 are formed. Thecoupling projections 131, 132, and 133 are extended and projected in adirection perpendicular to the outer circumferential surface, that is,the radius direction of the outer circumferential surface in thecircular sensing device (illustrated in FIGS. 2 and 3). The couplingprojections 131, 132, and 133 correspond to the coupling grooves 111,112, and 113 of the first housing 110, respectively.

In such a structure, when the second device 130 is positioned in thefirst housing 110, the coupling projections 131, 132, and 133 areinserted into the coupling grooves 111, 112, and 113 of the firsthousing 110, respectively, to support the sensing device 130.Accordingly, the sensing device 130 is housed in the first housing 110,without being moved.

Meanwhile, each of the coupling projections, for example, the couplingprojection 131 includes two bar-shaped members 131-1 and 131-2 separatedhorn each other in a direction parallel to the outer circumferentialsurface of the sensing device 110, in a state in which the couplingprojection is fixed to the outer circumferential surface. That is, thebar-shaped members 131-1 and 131-2 are separated from each other in thecircumferential direction in the circular sensing device illustrated inFIGS. 2 and 3. The bar-shaped members 131-1 and 131-2 may be formed ofan elastic member.

When the coupling groove 131 is inserted into the coupling groove 111 ofthe first housing 110 in a state in which the bar-shaped members 131-1and 131-2 are pressurized to each other, the outer surfaces of therespective bar-shaped members 131-1 and 131-2 are closely attached tosidewall surfaces of the coupling groove 111 by elastic forces of thebar-shaped members 131-1 and 131-2. Accordingly, the sensing device 130may be reliably fixed inside the first housing 10, without beingrotated.

Meanwhile, the length of each of the coupling projections of the sensingdevice 130, for example, the coupling projection 131, that is, thelength of the bar-shaped members 131-1 and 132-1 is equal to the depthof the coupling groove 111 of the first housing 110, that is, the radiallength of the coupling groove 111. In such a condition, when thecoupling projection 131 is inserted into the coupling groove 111 of thefirst housing 110, the front ends of the bar-shaped members 131-1 and131-2 are closely attached to the rear-end wall surface of the couplinggroove 111. The rear end indicates an end side of the radial direction.Therefore, the sensing device 130 is not moved in the radial directioninside the first housing 10.

Furthermore, the height of the coupling projection 131 of the sensingdevice 130, that is, the height of the bar-shaped members 131-1 and131-2 is equal to that of the coupling groove 111 of the first housing110, that is, the axial length of the coupling groove 111. In such acondition, when the coupling projection 131 is inserted into thecoupling groove 111 of the first housing 110 according to such acondition, lower-end surfaces of the respective bar-shaped members 131-1and 131-2 are closely attached to the bottom surface of the couplinggroove 111. Accordingly, the sensing device 130 is not moved in theaxial direction inside the first housing 10.

Meanwhile, contact projections 141, 142, and 143 are formed on the outercircumferential surface of the sensing device 130. The contactprojections 141, 142, and 143 are contacted with the innercircumferential surface of the first housing 110 to thereby inhibit thesensing device 130 from being moved or distorted in the radial directioninside the first housing 110.

The contact projections 141, 142, and 143 may be formed in such a shapeas to project in the radial direction. The contact projections 141, 142,and 143 and the coupling projections 131, 132, and 133 are alternatelyarranged on the outer circumferential surface of the sensing device 130.The contact projections 141, 142, and 143 may be selectively formed, andthe sensing device 130 may be more reliably housed in the first housing110 by the contact projections 141, 142, and 143.

After the sensing device 130 is positioned in the first housing 110according to the above-described structure, the second housing 120 iscoupled to the first housing 110. On the outer circumferential surfacesof the first and second housings 110 and 120, coupling portions 114 and124 are respectively formed, through which coupling means, for example,coupling screws (not illustrated) pass. As the coupling screws arecoupled to the coupling portions 114 and 124 in a state in which bothhousings 110 and 120 are set to face each other, the housings 110 and120 having the sensing device 130 fixed and housed therein are coupledto each other.

At this time, the upper end surfaces of the bar-shaped members 131-1 and131-2 composing each of the coupling projections of the sensing device130, for example, the coupling projection 131 are contacted with thelower-end circumferential surface of the peripheral portion of thesecond housing 120. Therefore, the upward movement of the sensing device130 is also limited.

Here, FIGS. 1 to 4 illustrate the sensing device 130 has a circularplate shape and the first and second housings 110 and 120 have acylindrical shape. However, the embodiment of the present invention isnot limited thereto.

That is, the sensing device 130 may be formed in a polygonal shapeincluding a triangle, and the first and second housings 110 and 120 mayhave a polygonal cylindrical shape of which the cross-section is formedin the same polygonal shape as that of the sensing device 130.

Meanwhile, as defined above, the sensing device 130 composing theembodiment of the present invention may include a steering angle sensingdevice, a torque sensing device, or a combination of the steering anglesensing device and the torque sensing device.

Hereinafter, an example in which the combination of the steering anglesensing device and the torque sensing device is used as the sensingdevice 130 will be described.

FIG. 5 is an exploded perspective view of the sensing device of FIG. 4,illustrating the combination of the steering angle sensing device andthe torque sensing device.

The sensing device 130 serving as the combination of the steering anglesensing device and the torque sensing device includes a first cover C1,a second cover C2, and a third cover C3.

Components of the torque sensing device are arranged between the firstand second covers C1 and C2, and components of the steering anglesensing device are arranged between the second and third covers C2 andC3.

The first to third covers C1 to C3 are coupled to each other toconstruct the sensing device 130 illustrated in FIGS. 1 to 4. Thesensing device 130 is housed in the first housing 110 to construct thepower steering sensor assembly.

Here, elements and functions of the torque sensing device and thesteering angle sensing device are known to those skilled in the art, andthe descriptions thereof will be omitted.

Meanwhile, referring to FIG. 5, the coupling projections 131, 132, and133 and the contact projections 141, 142, and 143, which have beendescribed above, are formed on the outer circumferential surface of thesecond cover C2. However, the embodiment of the present invention is notlimited thereto.

Although a preferred embodiment of the present invention has beendescribed for illustrative purposes, those skilled in the art willappreciate that various modifications, additions and substitutions arepossible, without departing from the scope and the spirit of theinvention as disclosed in the accompanying claims.

What is claimed is:
 1. A sensing device for a power steering sensorassembly, the sensing device comprising: a first cover; a second covercomprising a plurality of coupling projections disposed on an outercircumferential surface thereof; and a torque sensing device disposedbetween the first cover and the second cover, wherein the first coverand the second cover are configured to inhibit movement of the torquesensing device in an axial direction, and wherein the couplingprojections protrude in a radial direction of the second cover withrespect to an outer circumferential surface of the first cover.
 2. Thesensing device according to claim 1, wherein each of the couplingprojections comprises two bar-shaped members extended in a directionperpendicular to the outer circumferential surface of the second coverand separated from each other in a direction parallel to the outercircumferential surface of the second cover.
 3. The sensing deviceaccording to claim 2, wherein each of the bar-shaped members is formedof an elastic material.
 4. The sensing device according to claim 1,wherein the second cover further comprises a plurality of contactprojections each having a curved surface, extended in the radialdirection of the second cover, and formed on the outer circumferentialsurface of the second cover, and wherein each contact projection isconfigured to contact an inner circumferential surface of a housing. 5.The sensing device according to claim 4, wherein the couplingprojections and the contact projections are disposed on the outercircumferential surface of the second cover in an alternating fashion,such that each coupling projection is disposed between two contactprojections and each contact projection is disposed between two couplingprojections.
 6. The sensing device according to claim 4, comprisingthree coupling projections and three contact projections.
 7. The sensingdevice according to claim 6, wherein each of the coupling projectionscomprises two bar-shaped members extended in a direction perpendicularto the outer circumferential surface of the second cover and separatedfrom each other in a direction parallel to the outer circumferentialsurface of the second cover.
 8. The sensing device according to claim 7,wherein the coupling projections and the contact projections aredisposed on the outer circumferential surface of the second cover in analternating fashion, such that each coupling projection is disposedbetween two contact projections and each contact projection is disposedbetween two coupling projections.
 9. The sensing device according toclaim 6, further comprising a third cover coupled to the second cover.10. The sensing device according to claim 9, further comprising asteering angle sensing device disposed between the second cover and thethird cover.
 11. The sensing device according to claim 1, wherein thetorque sensing device is configured to connect to an input shaft and anoutput shaft.
 12. The sensing device according to claim 1, wherein theplurality of coupling projections are configured to be coupled to ahousing.
 13. The sensing device according to claim 1, further comprisinga third cover coupled to the second cover.
 14. The sensing deviceaccording to claim 13, further comprising a steering angle sensingdevice disposed between the second cover and the third cover.
 15. Thesensing device according to claim 1, further comprising three couplingprojections.
 16. The sensing device according to claim 15, wherein eachof the coupling projections comprises two bar-shaped members extended ina direction perpendicular to the outer circumferential surface of thesecond cover and separated from each other in a direction parallel tothe outer circumferential surface of the second cover.
 17. A sensingdevice for a power steering sensor assembly, the sensing devicecomprising: a first cover; a second cover; and a torque sensing devicedisposed between the first cover and the second cover, wherein thesecond cover comprises a plurality of contact projections formed on anouter circumferential surface thereof, wherein the first cover and thesecond cover are configured to inhibit movement of the torque sensingdevice in an axial direction, and wherein the contact projectionsprotrude in a radial direction of the second cover with respect to anouter circumferential surface of the first cover.
 18. The sensing deviceaccording to claim 17, wherein the torque sensing device is configuredto connect to an input shaft and an output shaft.
 19. The sensing deviceaccording to claim 17, wherein each of the plurality of contactprojections has a curved surface.
 20. An electric power steering systemcomprising: input and output shafts; a sensing device comprising a firstcover, a second cover, and a torque sensing device disposed between thefirst cover and the second cover; and a housing having the sensingdevice housed therein, wherein the second cover comprises a plurality ofcoupling projections disposed on an outer circumferential surfacethereof and coupled to coupling grooves of the housing, wherein thetorque sensing device is connected to the input and output shafts,wherein the first cover and the second cover are configured to inhibitmovement of the torque sensing device in an axial direction, and whereinthe coupling projections protrude in a radial direction of the secondcover with respect to an outer circumferential surface of the firstcover.